Multifunctional alumina/titania hybrid blocking layer modified nanocrystalline titania films as efficient photoanodes in dye sensitized solar cells

A facile way of fabricating efficient blocking layer on mesoporous TiO2 film of dye-sensitized solar cells (DSSCs) is demonstrated here for the first time. Al2O3 and TiO2 are combined together to form a blocking layer. A simple spin coating technique is employed which is a versatile and low-cost method over the atomic layer deposition (ALD) technique. Multifunctional alumina/titania (Al2O3/TiO2) hybrid overlayer is prepared on traditional TiO2 nanocrystalline thin film surface, through sequential deposition of AlCl3 center dot 6H(2)O and TiCl4 precursor solutions followed by sintering at 500 degrees C for 30 min. Al2O3 effectively plays its role in retarding interfacial recombination of electrons and improving open circuit potential (V-oc), while the tiny TiO2 clusters synthesized from TiCl4 treatment act as electron transporting channels to facilitate electron diffusion which leads to enhanced photocurrent (J(sc)). Compared to the device without blocking layer, the DSSCs assembled with Al2O3/TiO2 hybrid blocking layer showed improvement in J(sc) (from 13.09 mA/cm(2) to 16.90 mA/cm(2)) as well as in V-oc (from 0.72 V to 0.73 V) resulting a much better conversion efficiency of 8.60%. (C) 2015 Elsevier B.V. All rights reserved.